Upgrade to Reactor 2020.0.19

Includes Netty 4.1.77 and RxJava 3.1.4.

Closes gh-28437

Author: jhoeller

build.gradle

@@ -28,8 +28,8 @@ configure(allprojects) { project ->
 	dependencyManagement {
 		imports {
 			mavenBom "com.fasterxml.jackson:jackson-bom:2.12.6"
-			mavenBom "io.netty:netty-bom:4.1.76.Final"
-			mavenBom "io.projectreactor:reactor-bom:2020.0.18"
+			mavenBom "io.netty:netty-bom:4.1.77.Final"
+			mavenBom "io.projectreactor:reactor-bom:2020.0.19"
 			mavenBom "io.r2dbc:r2dbc-bom:Arabba-SR13"
 			mavenBom "io.rsocket:rsocket-bom:1.1.2"
 			mavenBom "org.eclipse.jetty:jetty-bom:9.4.46.v20220331"
@@ -67,7 +67,7 @@ configure(allprojects) { project ->
 			dependency "io.reactivex:rxjava:1.3.8"
 			dependency "io.reactivex:rxjava-reactive-streams:1.2.1"
 			dependency "io.reactivex.rxjava2:rxjava:2.2.21"
-			dependency "io.reactivex.rxjava3:rxjava:3.1.3"
+			dependency "io.reactivex.rxjava3:rxjava:3.1.4"
 			dependency "io.smallrye.reactive:mutiny:1.4.0"
 			dependency "io.projectreactor.tools:blockhound:1.0.6.RELEASE"